Lawyers filed suit in federal court Monday seeking to overturn Wisconsin’s ban on same-sex marriages and to block a state statute that makes it a crime to travel elsewhere for such a marriage.

The lawsuit, filed in US District Court in Madison, is the latest of several similar legal challenges across the country seeking to overturn state-level barriers to same-sex marriage.

Currently 17 states and the District of Columbia fully recognize gay marriages. Thirty states – including Wisconsin – have statutes or state constitutional amendments barring gay men and lesbians from entering into same-sex marriages.

The Wisconsin lawsuit was filed by lawyers with the American Civil Liberties Union, the ACLU of Wisconsin, and the law firm Mayer Brown, on behalf of four same-sex couples living in Milwaukee, Eau Claire, and Madison.

“These families simply want the security and recognition that only marriage provides,” Larry Dupuis, legal director of ACLU of Wisconsin, said in a statement.

“They have built their lives and raised children here. It is wrong for the state to treat these loving and committed couples as second-class citizens,” he said.

The suit asks the court to strike down the Wisconsin ban as a violation of both the due process and equal protection provisions of the US Constitution.

The lawyers argue that there is a fundamental right to marry, regardless of the gender of the spouses. Lawyers are also asking the court to invalidate sex specific language in the Wisconsin statutes that assign gender roles in a marriage – such as the terms husband and wife.

In addition the suit seeks a permanent injunction to block a state statute that makes it a criminal offense for a Wisconsin resident to leave the state to obtain a marriage that would be prohibited in Wisconsin.

Not only does Wisconsin not recognize out-of-state same-sex marriages, it criminalizes any effort by a state resident to enter into such a union. Violators are subject to punishment of up to nine months in jail and a $10,000 fine.

Mr. Dupuis said Wisconsin’s marriage evasion law was “cruel” in that it forced gay couples into “a Catch-22 where they can’t even travel elsewhere to obtain federal protections without their marriage being labeled a crime.”

Among the plaintiffs in the Wisconsin suit are Roy Badger and Garth Wangemann of Milwaukee, who have been together for 37 years.

Three years ago, Mr. Wangemann underwent cancer surgery. After medical complications, he was placed into a medically-induced coma for nearly a month.

Mr. Badger was granted power of attorney and used that status during the medical emergency to direct the care and treatment of his life-long companion. Had the couple been married such special legal status would not have been necessary.

According to lawyers in the case, when Wangemann’s prognosis became increasingly uncertain, Wangemann’s father sought to overturn Badger’s legal authority and have his son taken off life support.

Badger objected, and fought the attempt to challenge his legal authority. The issue was resolved when Wangemann emerged from the coma and recovered.

“What upset me the most was that after all of our time together, our relationship was not fully recognized by my family and there was a real danger that my wish to give Roy the ability to make decisions about my care could be stripped away,” Wangemann said in a statement.

“Thankfully, our wishes held in this case,” he said. “But without the protections that come with marriage, the consequences can literally be a matter of life or death.”

Lawyers for the suing couples say laws such as the Wisconsin ban treat same-sex couples as second-class citizens whose relationships are undeserving of the respect and protection afforded to opposite-sex married couples.

“More and more Americans over the past few years accept the idea that same-sex couples and their families shouldn’t be treated differently than other families,” John Knight of the ACLU Lesbian, Gay, Bisexual, and Transgender Project, said in a statement. “It is our hope that Wisconsin will soon join the other 17 states in granting the freedom to marry,” he said.